Sulphur-containing covering



Dec. 31, 1929. w.1-1. KOBBE 1,741,522

A SULPHUR CONTAINING QQVERING Original Filed Aug. 15 1926 INVENTOR BY MIAMI 0 ,MWa-uo ATTORNEY.

Patented Dec. 31, 1929 UNITED STATES PATEN -OFFICE WILLIAM HOFFMAN KOBBE, OF NEW YORK, N. Y'., AssIGNoR '10 TEXAS GULF s LrI UR COMPANY, oF BAY oI'rY, TEXAS, A CORPORATION OF TEXAS SULPHUR-CONTAINING COVERING Original application filed August 13, 1926, Serial No. 129,086. Divided and this application filed Apia 1a 1928. Serial massage.

This invention relates to coverings made of fabric and has for its object the provision coverings, preferably by impregnation of the fabrics with sulphur, imparts to the fabric such a degree of strength and/or rigidity as to render it admirably adapted for making coverings for numerous rigid articles. The

association of sulphur withfabrics, prefera bly by impregnation of the fabrics with sulphur, furthermore provides an intimate contact between the article covered and the sulphur impregnated fabric, through the contraction of the sulphur upon cooling. and

crystallization; The inventionth-us contemplates the provision of new articles of manufacture in the nature of coverings made in whole or in part of sulphur containing or sulphur impregnated fabric, and methods ofmaking the same. p

By fabric I mean. to include any pliable fibrous material, such as the various textiles,

felts and other cloth-like materials, made of either organic or inorganic fiber. 7 In particular, I mean to include fabrics made from asbestos or other mineral, fibers made of wool, silk, cotton, hair, jute, hemp, flax, wood pulp and other animal and vegetable fibres. More especially, I mean to include burlap, canvas,

cotton, flannel, all types of felt and in fact all classes of fabrics and/or textile products. In carrying out'the present invention, I

treat the fabric with sulphur so as to effect an,

association with the fabric of an appropriate amount of sulphur in such as to impart to the fabric. a desired degree of stu agth or rigidity. The desired association between thefabric and sulphur may be brought about in various ways, as for example, by impregnating the fabric with sulphur through immersion of the fabric in molten sulphur. The association of the sulphur with the fabric may also be accomplished by passing the fabric over rolls carrying molten sulphur, as well as by including solid sulphur in the fabric in any appropriate way and subsequently fusing the sulphur in contact with the fabric by the application of heat.

Heretofore metallic pipe lines and other structures which are installedunderground have been subjected to corrosive action. The corrosion of metal pipe lines in particular is a very serious problem especially in certain soils containing salts or other active chemicals. This is notably the case in the oil fields of the southwestern portion of the United States and portions of California. Insome cases the rapid corrosion of the pipe lines necessitates the removal or repair of these lines within two years and even within a shorter period. Destruction by saline waters of oil, well tubing is also very common in the same districts. v

' Elemental sulphur is chemically very rcsistant to the action of most reagents, it is impervious to water, and in many other respects is suited for protective purposes when applied to articles which are exposed to any of these reagents. The brittleness of elemental sulphur alone makes-it very difficult to apply to large: unbroken surfaces, and also makes materials covered in this manner very difficult to handle without rupturing the sulphur covering.

I have discovered a method of utilizing the protective qualitiesof sulphur as a covering for objects exposed to corrosion by associating the sulphur witha fabric. In accordance with the presentinvention, the article to be protecped is covered with a fahricimpreg natd with molten sulphur in such a way that following is an illustration ofthe protective covering of the invention as applied to a metal pipe A porous material in the nature of a fabric capable of absorbing a high percentage of molten sulphur is cut into strips of any appropriate width. The porous material, preferably a fabric, is then thoroughly saturated by passing it through a bath of molten sulphur. The impregnated fabric upon withdrawal from the bath and while the sulphur is still hot and molten, is then applied to a 'revolving'length of pipe or other similar material to be protected. The material on emerging from the bath of molten sulphur may be wound upon the pipe, either straight.

or spirally, orin any similar appropriate manner until a sufficient thickness of material is applied to the pipe. The thickness of the protective coating applied to the pipe or article being covered may be of any desired amountdepending upon the type of material and the condition of handling and service. For pipe covering, I have found a thickness of substantially one quarter of an inch sufficient to give satisfactory service, but this thickness may be increased or diminished so as to meet any given requirement. The molten sulphur as it contracts with the pipe attaches itself thereto and each succeeding layer of the sulphur impregnated fabric is closely welded to thelayer next below it by the molten sulphur absorbed within the fabric andadheringl to the surface thereof.

- lVhen a sufficient number of such layers are applied, the pipe with its covering of sulphur impregnated fabric is permitted to cool. In cooling the absorbed sulphur solidifies by crystallization with resulting contraction. This contraction not only bindsthe mass tightly'to the enclosed pipe, but results in a homogeneous monolithic stone-like covering.

In practicing the invention various textiles or fabrics are best suited for this purpose be'causeof their tensile strength and high de gree of absorption, but I prefer to use cotton flannel, felt or similar material, The strips may be ofany width so as to admit of application by wrapping spirally and obtaining thereby a uniformlysmooth covering. hen

spiral wrapping is employed, a strip offrom 3 to 6 inches wide is sufficient, but in some cases a wider -strip may be used-depending upon the.resiliency of the material and its ability to conform to the spiral wrappings.

A length of six inch line pipe, for example, approximately 20 feet long, is slowly revolved by mechanical means in a horizontal position while a strip of sulphur impregnated cotton flannel or other fabric is applied to the pipe.

Before the cotton flannel is applied to they pipe it passes through a bath ofmolten sulappropriate rolls or other mechanical means,

and applied to the revolving pipe upon which the impregnated material is .being wound. Such a strip of fabric is not only fully saturated with sulphur by its immersion in the bath, but it leaves the bath-and is wound on the pipe in a dripping condition, the temperature being such that solidification does not take place until the fabriohas passed around .the pipe and for an appreciable time there-- after; The subsequent plies are superimposed upon the preceding layer of this sulphurized fabric in the same manner, and in this way I build up a protective covering of an 'desired thickness by applying as many layers as may be necessary. In most cases four plies of the sulphurized fabric are suflicient to give adequate protection.

I The molten sulphur crystallizes after the covering has been applied as described. The crystallization takes place not only wlthin the fabric but between the plies thereof and at the same time increases in density which results in a: marked shrinkage. This shrinkage takes place not only when the liquid sulphur passes to the monoclinic stage of cryss tallization but again as this monoclinic sulphur graduall'y'changes to the stable rhombic condition In other words, the final and permanent state of thesulphur is materially less inally applied, and this action is largely responsible for the great strength, homogenity and imperviousness of the finished covering. Such a covering may consist-of from 7 5 to of sulphur by weight, depending upon the porosity of the material used and the quantity of excess sulphur thereon when applied to thepipe. This results in whatis in fact a monolithic or stone-like covering bonded not only to the pipe surface but each layer bonded to the adjacent layer with no indica-.- tion of'se'parate and distinct layers. This sulphur impregnated fabric'eovering is ex-, tremely tough, and can only be removed from the pipe by resorting to such means as a cold chisel or some similar cutting and wedg'ing operation, or by means of the application of sufficient heat to melt the crystallized sul-.

h'ur. l

in mass than that of the molten material origr a metal pipe covered with the sulphur impregnated fabric of the invention. The-pipe is cut away so as to better illustrate the pipe and the nature of the covering.

Fig. 2 of the drawing is a sectional view showing the manner of applying the impregnated fabric covering of the invention to the thread and coupling ends of a metal pipe.

In the drawing a metallic pipe 5 is covered with the monolithic sulphur impreg- ,nated coverin-g'fi of the invention. The contraction of the sulphur upon crystallizingcauses the covering 6 to draw'tiglitlyabout the exterior of the pipe from all sides with equal force, so that the bond between the pipe 5 and the covering 6 is made infinitely tight and the whole mass of the covering 6 is bound by the force ofcrystallization into a monolithic or stone-like structure by thesurface of the covering 6', but are bound or cemented firmly by congealed sulphur.

The fibrous nature ,of the fabricused in the covering 6 bindsthe brittle or frangible particles of sulphur together infsuch a mannertha't'the covering assumes not only a rigid form but a tough structure as well. The

shrinkage of the coveringmaterial brought about by crystallization causes the wholemass to assume such a dense form that-thevariouslayers of which the covering is built are thoroughly merged into one another and.

are not visible when the covering is broken or cut as shown in the drawings.

In Fig. 2 of the drawing when'coveringpipes which have threaded connections for attaching one length of the pipe to the next adjoining length, I prefer to screw a coupling securely to one end of the pipe 5 before covering it with the sulphur impregnated fabric 6.1 The threads 8' at the opposite end of the pipe may be appropriately protected a before the, sulphur,impregnated fabric is ,b at

v ture of filler and sulphur along with it and endl i of the attached coupling 10 and terminated at the point 9 where the pipe.-

and, produces a pipe covering of great applied. The sulphurimpregnated fabric 6 1s then applied to the pipe from the extreme threads 'begintnear the opposite'end of the pipe; thus these threads 8 are left exposed.

1 When one-covered-pipe' is screwed into the that a permanent; bond is made between the newly applied material and the. covering alnext covered pipe,.the exposed. threads 8 are almost entirely covered by the coupling .10 of the adjoining pipeand the protective covering of one plpe approaches very closely the protective covering of the n ext adjoinmg pipe.' The short intervening space be-.

tween the coverings is vthen wound manually with sulphur impregnated fabric of the same, or like nature as the material Which was used for th e protective covering 6. The molten 'sulphurpf this manually applied strip melts a sufiicient portion of; the sulphur-inf the,

already. {sulphur impregnated covering so ready on' the pipes.

,Bolted, flanged or riveted pipe joints-are notcogered with the protective covering until after'the coated lengths of pipe'areqjomted together. The joints are then covered manually by means of sulphur impregnated strips length ofthe pipe or being covered.

.76 example given herein. Thls, method may be, varied vin many details, without departing from the spirit of the invention. Thus, for;

example, a pipe .or other structure may be. straight wound rather than spirally. This necessitates strips preferably as wide as the other structure I which is The pipe, or {other structure, on the other hand,. may be wrapped with the requisite number of plies'of fabric and-then immersed as awhole in the saturating bath. This procedure, however, is not economical and is wasteful of heat for by thismethod it is neces sary to raise the metal of the'structure being covered to the temperature of the bath before impregnation can be fully brought about, and

the whole massmust be then subjected to cooling upon its removal fromthe bath before complete crystallization can take place.

'I' prefer to use elemental sul hur as the impregnating means for the fa .ric, but it is add an inert filler to the sulphur, in order to produce a sulphur composition possessing greater strength and/or resistance. than can be obtained by sulphur alone. An inert filler of-this nature having a specific gravity approximating that of sulphur and in a finely ground state, maybesuspended in the imregnating bath approximately in equal parts y' weight.- The abric passing through a made up in this manner carries the IIllX- although it may penetrate the fabric only in part, it adheres to the surface of the fabric strength, imperviousness and tenacity. It

will be understood that the'invention is not phur-impregnated fabric, which" comprises impregnating fabric in a bath of molten suljphur ata temperature of substantially 150 G.,.wrapping the hot, sulphur-impregnated fabric upon the article to be covered, causing the temperature of the sulphur-impregnated fabric to be'lowered and the sulphur to contract and solidify in crystalline form Within the-lnterstices of the fabric.

sometimes desirable," for various reasons to 2. An article having a protective covering firmly attached thereto, said covering comprising a fabric having its interstices filled with crystalline sulphur.

3. An article having a protective covering 5 firmly attached thereto, said covering comprising a monolithic sulphur-impregnated fabric containing from 75% to 95% of sulphur.

4. An article having a protective covering firmly attached thereto, said covering comprising a monolithic sulphur-impregnated fabric.

In testimony whereof I affix my signature; WlLLIAM HOFFMAN KOBBE. 

